Path: utzoo!mnetor!uunet!husc6!mailrus!ames!pasteur!ucbvax!hplabs!hpda!hp-sde!hpfcdc!bayes
From: bayes@hpfcdc.HP.COM (Scott Bayes)
Newsgroups: comp.sys.mac.programmer
Subject: Re: writing XCMDs
Message-ID: <11550003@hpfcdc.HP.COM>
Date: 4 May 88 16:28:44 GMT
References: <3127@saturn.ucsc.edu>
Organization: HP Ft. Collins, Co.
Lines: 24

An interesting wipe might be one I've seen ESPN and some other broadcasters
use in sports telecasts, usually with title announcements superimposed:

Average the to-be-displayed card over some large rectangular or square
tiling (eg over 64x64 tiles) for the whole screen and display all tiles.
Then cut the rectangles in half in both x and y, giving 4 times as many
tiles, and average over those.  Iterate until you have the 1 pixel
resolution of the final display.  It's a neat effect, almost like
focussing a lens on the the display, gradually getting the focus better
and better.

It may be better in colour than in mono, as the mono will probably tend to
produce "blots" until the resolution increases to near the feature size of
the picture on the card.

Larry Fenske invented something like this to incrementally focus on a
Mandelbrot display, in a program we wrote some years ago. It was quicker
than a scan-line-oriented painting algorithm for quickly deciding whether
the current computation/viewing rectangle contained any features of interest,
as you could "kind of" see the whole rectangle, instead of waiting for the
scan-line painting to move down the screen.

Scott Bayes
hpfclw!bayes